1) Field of the Invention
This invention relates to a process and an apparatus for treating suspended substances such as active sludge, flocs, etc. in a liquor. The present invention is applicable to sewage treatment plants for treating organic substances suspended in a sewage with active slude, to waterworks for making drinking water by purifying the raw water from rivers, to culture plants for culturing microorganism, bacteria and yeasts, to plants for producing lactobacillus such as chlorella, etc. and medicines such as penicillin, etc., to plants for filtering suspended substances in a liquor, to dephosphorizing plants for removing phosphorus components contained in water, etc.
2) Prior Art
In waterworks and sewage treatment plants, it is a general practice to purify water by precipitating suspended substances in a liquor, such as active sludge, etc. by gravity. When the suspended substances in a liquor are not precipitated or the precipitation state is deteriorated, the suspended substances flow out together with treated water, thereby deteriorating the water quality.
Heretofore, the coagulation state of the suspended substances has been visually observed or measured by manual analysis, and the settlability has been evaluated by the experiences and the sixth sense of operators on the basis of the thus obtained results. The present inventors have proposed a process for judging the precipitation state of active sludge at the time point of measurement by image-processing the existing state of coagulating microorganisms (zoogleal microorganisms) and filamentous microorganisms in a sewage treatment plant. The process is disclosed in Japanese Patent Application Kokai (Laid-open) No. 60-31886. The present inventors have also proposed a process for evaluating the precipitation state at the time point of measurement by determining the settlability of flocs from the luminance information of flocs obtained by image processing. The process is disclosed in Japanese Patent Application Kokai (Laid-open) No. 60-31886.
According to the above-mentioned prior art, only the settlability at the time point of measurement is judged. In other words, even if the settlability is good at the time point of measurement, it is impossible to tell how the settlability will be in the future. It is too late to take further steps after poor settlability has been recognized.
It is really necessary to evaluate at the time point of measurement what direction the precipitation state will take in the future and then take appropriate steps.
The above-mentioned prior art fails to provide a process for predicting the future precipitation state, and thus cannot predict the future precipitation state.